Comparison of populations of human faecal bacteria before and after in vitro incubation with plant cell wall substrates

Human faecal slurries were incubated anaerobically with larchwood xylan, oat spelt xylan, wheat bran, apple cell walls or sugar beet pulp as sole carbon sources. The populations which developed during incubation were different from the inoculum, the most marked changes being an increase in the number of Bacteroides species and a decrease in the number of Fusobacterium species for all carbon sources tested. With a water-soluble preparation of larchwood xylan the population was dominated by species able to ferment this substrate, in contrast to the population which developed with the insoluble substrates. The ability to use one plant cell wall substrate appeared to be related to the ability to use others. Strains capable of using plant cell wall substrates included Bacteroides spp., Clostridium clostridiiforme, Bifidobacterium longum, Fusobacterium spp. and Escherichia coli. When incubation with two contrasting substrates (bran and larchwood xylan) was replicated, the populations which developed were reproducibly different from the inoculum and from each other.     

Improved Yield of Aflatoxin by Incremental Increases of Temperature

Increasing the initial temperature of the rice fermentation of Aspergillus parasiticus NRRL 2999 from 15 to 21 C after 24 h of incubation and then to 28 C after 48 h resulted in about a fourfold increase in total aflatoxin over the usual fermentation which is held constant at 28 C for 6 days. The percentage of aflatoxin B(1), the most toxic component, in the total aflatoxin was also increased.     

The Role of the Val66Met Polymorphism of the Brain Derived Neurotrophic Factor Gene in Coping Strategies Relevant to Depressive Symptoms

Disturbances of brain derived neurotrophic factor (BDNF) signalling have been implicated in the evolution of depression, which likely arises, in part, as a result of diminished synaptic plasticity. Predictably, given stressor involvement in depression, BDNF is affected by recent stressors as well as stressors such as neglect experienced in early life. The effects of early life maltreatment in altering BDNF signalling may be particularly apparent among those individuals with specific BDNF polymorphisms. We examined whether polymorphisms of the Val66Met genotype might be influential in moderating how early-life events play out with respect to later coping styles, cognitive flexibility and depressive features. Among male and female undergraduate students (N = 124), childhood neglect was highly related to subsequent depressive symptoms. This outcome was moderated by the BDNF polymorphism in the sense that depressive symptoms appeared higher in Met carriers who reported low levels of neglect than in those with the Val/Val allele. However, under conditions of high neglect depressive symptoms only increased in the Val/Val individuals. In effect, the Met polymorphism was associated with depressive features, but did not interact with early life neglect in predicting later depressive features. It was further observed that among the Val/Val individuals, the relationship between neglect and depression was mediated by emotion-focused styles and diminished perceived control, whereas this mediation was not apparent in Met carriers. In contrast to the more typical view regarding this polymorphism, the data are consistent with the perspective that in the presence of synaptic plasticity presumably associated with the Val/Val genotype, neglect allows for the emergence of specific appraisal and coping styles, which are tied to depression. In the case of the reduced degree of neuroplasticity expected in the Met carriers, early life adverse experiences are not tied to coping styles, and hence less likely to be translated into depressive states.     

Diversity-oriented synthesis of bicyclic fragments containing privileged azines

An innovative and efficient reagent- and scaffold-based diversity oriented synthesis (DOS) of a fragment set was developed for fragment-based drug discovery (FBDD) programs. Twelve diverse, functionalized and bicyclic scaffolds were rapidly accessed by adopting a convenient synthetic toolkit around three privileged azine cores in order to effectively modulate biomolecules. These structures are characterized by both key motifs for interacting with diverse biological targets via hydrogen bonds and useful points of growth for subsequent fragment optimization.     

Biodiversity of Belowground Invertebrates as an Indicator of Wet Meadow Restoration Success (Platte River, Nebraska)

Soil invertebrate communities are fundamental components of wet meadow ecosystems. We compared soil invertebrate biodiversity between restored and native wet meadows to assess the effectiveness of restoration practices. Biodiversity and biomass were measured in 2002 and 2003 from four native and three restored sites located along a 100-km stretch of the Platte River in south-central Nebraska. The sites ranged in age from 3 to 6 years since restoration. Samples were collected during May, July, and September each year. Soil temperature, soil moisture, percent litter cover, and root mass were measured at each site. Twelve 20 × 20 × 25–cm soil blocks were extracted at each site; soil was washed through a 1-mm sieve; and invertebrates were identified, counted, and weighed. Native sites had higher Shannon and Simpson diversity values and contained greater invertebrate biomass than restored sites. Five invertebrate taxa (isopods, scarab beetles, click beetles, earthworms, and ants) were collected with enough frequency to assess restoration effects on their occurrence. Of these, only ants occurred more frequently in restored sites. Restored sites generally had less litter cover, lower root mass, lower soil moisture, and higher soil temperature than native sites. Current restoration practices may not be completely effective at returning sites to native conditions. Physical reconstruction of wet meadow topography and high-diversity reseeding may not be adequate to fully restore soil invertebrate communities, even over extended periods of time.     

Abnormal elevation of the neural folds in the loop-tail mutant mouse.

The processes of elevation and convergence of the spinal neural folds were analyzed in normal (+/+; Lp/+) and abnormal (Lp/Lp) embryos of the loop-tail mutant mouse in order to determine possible mechanisms underlying the dysraphic defect characterized by a failure of the neural fold to close in this mutant. The results indicate that the neural folds are already defective during very early phases of elevation, with greater distances between the apical points of the paired walls of the neural groove, larger ventral angles and higher ratios of luminal/basal linear distances occurring in the abnormal embryos relative to those in normal embryos. The cross-sectional area of the neuroepithelium is also greater in abnormals, suggesting that faulty elongation of the neuraxis may contribute to the dysraphic condition.     

Membrane topology of the endoplasmic reticulum to Golgi transport factor Erv29p

Secretory proteins are transported from the endoplasmic reticulum to the Golgi apparatus via COPII-coated intermediates. Yeast Erv29p is a transmembrane protein cycling between these compartments. It is conserved across species, with one ortholog found in each genome studied, including the surf-4 protein in mammals. Yeast Erv29p acts as a receptor, loading a specific subset of soluble cargo, including glycosylated alpha factor pheromone precursor and carboxypeptidase Y, into vesicles. As the eukaryotic secretory pathway is highly conserved, mammalian surf-4 may perform a similar role in the transport of unknown substrates. Here we report the membrane topology of yeast Erv29p, which we solved by minimally invasive cysteine accessibility scanning using thiol-specific biotinylation and fluorescent labeling methods. Erv29p contains four transmembrane domains with both termini exposed to the cytosol. Two luminal loops may contain a recognition site for hydrophobic export signals on soluble cargo.